This invention relates primarily to a ball, a plug or a butterfly valve. (It may even pertain to a rising stem valve.) Ball, plug or butterfly valves have a stopper that interrupts fluid flow when rotated 90.degree.. In conventional valve designs, a shaft is attached to the stopper and the shaft is actuated by an external handle. The shaft is surrounded by a ring or rings of packing that maintain the pressure in the valve.
This invention relates to magnetically actuated packless valves for high pressure applications. Related patents pertaining to magnetically actuated valves, but not especially for high pressure environments say in excess of 1000 to 2000 psi, are described in U.S. Pat. Nos. 3,347,262 and 3,747,892. Aspects of this invention relate to my own U.S. Pat. No. 4,106,825. See also my copending application Ser. No. 39,900, filed May 17, 1979 now U.S. Pat. No. 4,284,262, dated Aug. 18, 1981, entitled "Magnetically Actuated Stopper Valve".
The known advantage of magnetically actuated valves is the elimination of the stuffing box which has always been a drawback. However, in the past, the use of these valves has been confined to relatively low pressures. The principal reason has been that sufficiently strong permanent magnets did not exist that would actuate the magnetic valve through the thick walls required to contain high pressures. Newly available permanent magnets permit the use of thicker walls in the valve housing providing the possibility of magnetically actuated valves for use at high pressures.
It is an object of this invention to provide a magnetically actuated valve which will reliably open and close. It is a further object to provide a magnetically actuated valve with a fail-safe manual override.